Advertisements are increasingly being used by web site operators as significant sources of revenue. Advertisements are often provided in the form of banners, textual advertisements, pop-ups, or the like. When a user clicks on an advertisement, the user may be taken to a web site or other network resource that features a product or service highlighted in the advertisement.
Web site owners often contract with advertising partners to display advertisements on the web site owners' web pages. A web page on a web site might, for instance, include advertisements provided by an advertising partner's servers. The advertisements selected by the advertising partner may be randomly selected. Alternatively, the advertisements may be more targeted toward users. For example, advertisements may be selected that closely match one or more keywords listed on the web page the user is viewing or on a web page the user has viewed. Oftentimes, however, the subject matter of these advertisements does not align with the current preferences or interests of the viewer.